872. | 341 [Cope. 
there is but one smooth surface gradually narrowing with the thinning of 
the bone from the condyle. 
The premawillary is less extended antero-superiorly than in the species 
already described, but supports, as in it, an articular face. There is no 
groove behind it, as in L. anaides and Portheus. It displays a surface for 
osseous articulation to near its extremity on the inner side, while below 
it, and on the external face, near the basis of the first and second teeth, 
the surface is rugose ; maxillary teeth 43. The dentary supports 25. The 
anterior hook is obtuse, and rises abruptly to above the apices of the 
crowns of the teeth. It is knobbed above, and supports a tooth not 
larger than the others. 
Allthe cranial bones. preserved are not sculptured. 
Portions of the thin flat spines display the delicately-grooved striation 
already observed, while the trenchant edge is bordered on one side by 
raised longitudinal strie. The other side is minutely pitted. 
The vertebra are anterior, and without lateral grooves. Three of 
them are M. .06 in length ; an undistorted one is a little wider than deep, 
and the cup is .026 across. 
Measurements. 
M. 
Length ramus mandibuli.....-.--+-- ie ti es a ae 
Depth at symphysis......---- pacutestt Side 5 5 uate ee es) 
“ premaxillary (oblique).....---- ser ote tee 043 
Length be ie Satine eer cites os UO. 
Depth maxillary at condyle...-.--+++++++++> pe as 
ee ae polind . 7%. 5 6. sk casts oe ce ene 038 
ce < near middle...........+22++- rea ee 
Width flat spine. .....25--.+s sere eee tes Peicee hee .031 
This species, and the two preceding, were not very unlike in size; the 
two following are smaller. 
ICHTHYODEOTES PROGNATHUS. Cope. 
Proceed. Amer. Philos. Society, November, 1870. (Sawrocephalus.) Hay- 
y ( i NE 
den’s Geol. Survey, Wyoming, etc., 1871, p. 417.) 
In this species the premaxillary is more rhomboid in outline than in 
the others, and is less convex externally. Of its more numerous teeth, 
the first is not larger than the last, differing thus from all others of the 
genus, and it is in line with the nearly straight anterior margin of the 
bone. It is more compressed than in the other species, whence I origi- 
nally placed it in Saurocephalus. To this genus it doesnot belong, as the 
absence of marginal alveolar foramina shows. The surface of the bone 
is peculiar ; in a minute sculpture of impressed lines, or lines of puncte. 
There is a very small articular surface on the superior extremity. 
From the North Fork of the Smoky River. 
